The invention relates to air-cooled internal combustion engines, and in particular to a single cylinder diesel engine that is provided with a crankshaft which rotates about a vertical axis and has a capsule type casing that surrounds the cooling air channels.
In the case of air-cooled engines where the shaft runs vertically in the mounting position, one usually finds that these are Otto carburetor engines for special applications, e.g., to drive lawn mowers, agricultural equipment, or similar machines. These vertical shaft engines often omit a reverse gear, but allow the height of a piece of equipment into which they are incorporated to be especially low. Usually, such engines are not designed for continuous duty; their power range usually being between 2 and 5 kW.
Known small diesel engines for industrial applications are usually standing motors, i.e. units which have a crankshaft that rotates about a horizontal axis in the mounting position, and are units of robust construction, suitable for multifunctional applications, and which often are provided with noise-inhibiting casings to protect the environment against excessive noise emission. Where single cylinder diesel engines are concerned, the power range of industrial diesel engines of this type have an upper limit of approx. 12 kW, at a working volume of 700 to 750 cm3.
In the case of an oil-cooled single cylinder engine, (as described in U.S. Pat. No. 4,964,378), a partial enclosure is provided for additional air cooling. A cooling air blower at the upper end of the crankshaft serves to divert a cooling air stream, which is led along the ribs of the crankcase enclosure; a second cooling air stream is channeled through a capsule type casing that surrounds the cylinder and the cylinder head. The two cooling air streams are evacuated separately. On the bottom surface of the enclosure, where the lower end of the crankshaft is located, a capsule type enclosure of the engine housing is omitted. In this area, the cooling is accomplished solely by the oil in combination with the housing""s ribbed walls. Such a motor is therefore dependent on a combination of air and oil cooling, which translates into high manufacturing costs.